1. Field of the Invention
The present invention relates to a transmission system, and more particularly to a direct transmission system for a bicycle or the like.
2. Description of the Prior Art
A direct transmission system for bicycles is disclosed in U.S. Pat. No. 3,861,715 to Mendoza. In this patent, the bicycle hub is driven to rotate by the shaft 20 via an engagement between the conical gear 25 and the conical gear portion 40 of the mobile cone 39. The axle 31 of the bicycle rear wheel is fixed to the lower back fork of the bicycle. One end of the axle 31 is fixed to the tube 27 by means of an angled beam 34, which is welded on one end to the tube 27. A box 58 is provided to house the direct transmission system of the bicycle.
The direct transmission system has at least the following two problems. First, one end of the axle 31 which is fixed to the angled beam 34 is fixed in place by the spacer 36 and the nut 35 and is housed by the box 58. This is very inconvenient when the bicycle has a flat tire and when the rear wheel has to be removed from the lower back fork of the bicycle in order to repair the flat tire. The box 58 should be removed before the axle 31 can be detached. Second, the shaft 20 may move longitudinally so that the conical gear 25 which is fixed to the rear end of the shaft 20 may be separated from the engagement with the conical gear portion 40 of the mobile cone 39.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional direct transmission system.